Tension rods have been used for many years to support curtains or room dividers. Typically, tension rods differ from curtain rods as tension rods generally don't require extra structural hardware, like hanging brackets, to hold and connect the rod to the wall. Instead, tension rods generally contain spring-loaded mechanisms that create an outwardly-projecting force within the rod to allow the two ends of the tension rod to press against two vertical surfaces or walls which support the tension rod and the curtain or room divider without the need for additional structural support. In the case of a traditional curtain rod (in cases of curtains or drapes used to cover windows or openings) generally a curtain rod is used because of the desire to provide movable covering of windows or openings. In curtain rod constructions, support brackets are placed in generally-regular and short spacing to support the curtain rod properly against a wall.
When a curtain or room divider is wanted to span between two walls for the sake of creating two temporary spaces out of one larger space, a curtain rod with occasionally-spaced support brackets from the ceiling may be used; however, the curtain or room divider may not be opened fully because of the connecting support brackets from the ceiling. In the past, tension rods have been used to minimize the need for support brackets in the ceiling. Tension rods work well due to a high-tension helically-wound spring located inside of two metal tubes of differing but concentric diameters. When used, the unsupported tension rod may allow the full opening of the curtain near the support walls, this enables one to turn the divided space back into one larger space. Generally, to keep costs and weight down, tension rods are made of thin-walled (0.020″ or 0.05 mm) steel tubing. Decorative and supportive end caps are generally cast of machined metal with rubber compression pads situated between the support wall and end cap.
However, there are several shortcomings in current tension rod technology. Because of structural limitations of commercially-available designs, tension rods are generally designed for a maximum span of approximately 10 foot (3.05 meters) between walls. In many places around the world, a room span of 12 feet (3.66 meters) has become more the norm. Therefore there is a need for a tension rod capable of addressing a 12-foot or longer span. Because tension rods are generally shipped from a retailer to the user via a shipper like United States Postal Service, United Parcel Services, FedEx, and DHL, length of the shipping package can be a factor in economical shipping. Recent changes have shortened the length of shipping boxes with the said shippers from 72 inches (183 cm) max to 60 inches (152 cm) max without a significant increase in shipping costs. However, the actual length of a ready-to-ship tension rod needs to be closer to 58 inches due to the inner dimension of a 60-inch long shipping box plus a potential inner retail box (147.3 cm). Many of the currently-produced tension rods will not fit under this constraint even after full collapse of the tension rod. Moreover, a collapsed-for-shipping tension rod to span a 12.5 foot-150-inch (366 cm) space, as discussed above, would not be able to come under the new maximum shipping length. Conventional Tension Rod technology for a 10 foot-120-inch (304.8 cm) Tension Rod has a ready-to-ship collapsed length of 64.5 inches (163.8 cm) while a 12.5 foot-150 inches (381 cm) Tension Rod would have a ready-to-ship collapsed length of 79.5 inches (201.9 cm). Therefore there is a need to keep both 10-foot and 12.5-foot tension rods under the maximum length for shipping yet span the long spans desired with a newly-designed shorter tube length plus an extension tube system.
In addition, when creating a tension rod of longer span while minimizing the addition of weight creates challenges in keeping the tension rod from bending excessively when a longer rod is loaded with the additional curtain or divider fabric to span the additional distance in longer rods. Thus there is a need for a tension rod that traverses a longer span without additional bending of the rod due to the span and weight of the additional materials.
Current tension rod systems typically comprise of eight parts assembled into one functioning mechanism. Generally, tension rods are limited to short span differences due to the limitations of the compressed spring. In the past, different tension rod system sizes could be made to address the needs of various spans such as: 28-48 inches (71-122 cm), 48-80 inches (122-203 cm), or 80-120 inches (203-305 cm). This would be achieved with the use of different length components in a similar method of assembly and function. However, these parts are changed for each size or rod, therefore there is a need for a tension rod system that allows both systems to have the same exact parts except for one change part to address difference in length while providing both to ship economically under shipper's maximum length constraints.
In addition, in long-gap applications, a connector is needed to connect the main tension rod subassembly with the with a cap assembly. Past connectors used for tension rods have been metal rods or expansion clamp technologies. Solid metal rod systems are inexpensive connectors but they have issues with fitting properly due to the variation in the size of the connector outer diameter and inner diameter of the corresponding tubes. If too tight, it's difficult to insert; if too loose, it can result in excessive sag of the tension rod. Expansion clamps are more robust as they have two half-round shaped parts that expand outward when set screws are used to force the two main parts to move outwardly against the inner surface of the tubes. The issue with the current expansion clamps is that they have intricate, difficult-to-machine interlocking surfaces that may separate when initially inserted into the tension rod tube. Thus there is a need for an improved expansion clamp.
An issue with current tension rod designs is that they are limited to a maximum of about 54 in-lbs of force before the internal spring fails. Spring failure could result in the tension rod to not produce needed compressive forces to support the tension rod and room divider. Thus there is a need for a more robust spring design. Current tension rod technology generally only has a one-inch optimum range for spring compression in the assembly. This optimum range is the difference between minimum force to support the tension rod and room divider assembly to a wall and the maximum force before spring failure. In addition, past springs generally have failed to provide the proper outside of a small range of insertions, thus there is also a need for a spring that has a greater range of applications.
These problems, and others, have been addressed by the improved tension rod and room divider discloser herein and discussed in greater detail below.